Two stage impact fuze

ABSTRACT

A two-stage omni-directional impact fuze having a firing pin assembly and a rotor containing a detonator. A pressure actuated locking arm assembly allows for the rotation of the rotor to the first stage arming position, while the removal of a wind tab allows for the rotation of the rotor to the second stage or fully armed position. In this position under impact in any direction a spherical weight located adjacent to the firing pin assembly causes movement thereof against the detonator and subsequent detonation of the fuze. It is this pressure actuation in conjunction with two-stage arming and omni-directional impact detonation which makes this fuze extremely safe and reliable in operation.

United States Patent Wesson et a]. 1 July 25, 1972 [54] TWO STAGE IMPACT FUZE 3,047,259 7/1962 Tatnall et al. 102/4 x [72] Inventors: Jerry J. Wesson, Winter Park; Thomas W. Bouher, Mamand, both of Fla [73] Assignee: The United States of America as Primary Examiner-"Samuel Engle represented by he Secretary f the Auorney-Harry A. Herbert,.lr. and Jacob N. Erlich Force I [57] ABSTRACT [22] Filed: Oct. 6, 1970 A two-stage omni-directional impact fuze having a firing pin [21] PP N05 90,184 assembly and a rotor containing a detonator. A pressure actuated locking arm assembly allows for the rotation of the rotor [52] us Cl 102/76 R 102/73 A 102/81 to the first stage arming position, while the removal ofa wind 51 Int. Cl. ..FiZc 5/00 allqws the swmd 5mg: [58] Field of Search ..f1o2/70 81 81.2 4 76 73 fully armed impm i direction a spherical weight located adjacent to the firing pin assembly causes movement thereof against the detonator and [56] References Cited subsequent detonation of the fuze. It is this pressure actuation in conjunction with two-stage arming and omni-directional UNITED STATES PATENTS impact detonation which makes this fuze extremely safe and reliable in operation. 2,853,011 9/1958 Will et al ..l02/8l.2X 2,420,237 5/1947 Girouard 1 52/8 I .2 10 Claims, 6 Drawing Figures .16 '2 (a -'4 ,I J

Patented July 25, 1972 3,678,859

3 Sheets-Sheet 2 INVENTORS. Jzxm J. Wissnz,

77/0004: W o 1.752 BY Patented July 25, 1972 3,678,859

3 Sheets-Sheet 5 INVENTORS fizzy J7 WA'ssaN rwanms w. oun- 2 TWO STAGE IMPACT FUZE BACKGROUND OF THE INVENTION This invention relates generally to impact fuzes, and more particularly to a fuze which is capable of being safely armed and yet capable of omni-directional impact detonation.

A fuze is a mechanism for igniting or detonating the bursting charge of any munition, such as a projectile, and performs this function either upon impact or at a certain time during flight. The purpose of safing and arming fuzes is to provide safety to the personnel during the handling and storage of the fuzes while permitting placement of the munition containing the fuze in the desired position over the target area before the munition is armed. This munition is then exploded on the target by the initiation from the fuze upon impact thereof. Various ways have heretofore been employed for the prevention of deployment. Among these are fuzes utilizing pressure sensing devices using barometric pressure, highly complex electric circuitry, acceleration setback devices, centrifugal arming devices, and fuzes utilizing lanyards, propellers, anemometers, timers, etc. Most of these systems require flutes, vanes or other protuberances on the munition to activate the fuze arming sequence. Other munitions must be stabilized so that they will impact the target in a specific attitude so as to cause initiation of the explosive charge by the fuze. All such protuberances increase the size of the fuze and therefore affect the packaging efficiency ofthe munition within a carrier, such as a missile or dispenser.

It can therefore be clearly seen that there exists a need for a munition containing a safing and arming fuze which has the following characteristics:

1. It should have no protuberances thereon;

2. It should be capable of being used with a non-stable aerodynamic configuration and/or a non-spin munition;

3. It should have a small diameter and low silhouette so as to require a minimal volume within the munition;

4. It should be omni-directional in impact initiation so that munition orientation is not required;

5. It should be capable of being produced on high production type machinery; and

6. It should be extremely safe and reliable in operation.

SUMMARY OF THE INVENTION The safing and arming fuze of this invention overcomes the problems set forth hereinabove.

The instant invention is an omni-directional impact, twostage arming fuze. It is so designed as to prevent pre-target detonation by keeping the detonator 180 away from the firing pin until the munition is satisfactorily deployed. Furthermore, case separation in the operational sequence of the fuze of this invention, provides a visual indication of the first stage arming should the fuze inadvertently become armed during handling and storage.

The first stage arming of the fuze of this invention is accomplished by warhead pressurization of the device and the second stage arming occurs by the removal ofa wind tab when it is subjected to the high velocity air stream after deployment. The all ways" or omni-directional impact capability of this invention is provided by a spherical weight located within the fuze which moves between two converging conical surfaces. One of the conical surfaces, which is an integral part of the firing mechanism, is capable of being depressed at impact, regardless of the submissile or munition orientation.

The advantage of the fuze of this invention is that it utilizes pressure for the first stage arming, a wind tab for the second stage arming, and provides omni-directional impact detonation capability. These features eliminate the need for a stabilization device or other protuberances on the munition, thereby providing a savings in the manufacture of the submissile by decreasing both its complexity and size. This also increases the packaging efiiciency of the munition within a container, dispenser, or missile. In addition, the fuze of this inven- .pre-target detonation of these munitions'during tactical tion is designed so that a minimum of operations are required for its production.

It is an object of this invention to provide a two stage omnidirectional impact fuze which requires no protuberances thereon, is of small diameter and low silhouette and is capable of being used within a non-stable aerodynamic configuration and/or a non-spin munition.

It is another object of this invention to provide a two stage omni-directional impact fuze which is capable of arming and detonatjng in any orientation.

It is a further object of this invention to provide a two stage omni-directional impact fuze which is extremely safe and reliable in operation.

It is a further object of this invention to provide a two stage omni-directional impact fuze which utilizes high pressure for the first stage arming.

It is still a further object of this invention'to' provide a two stage omni-directional impact fuze which utilizes the combination of high pressure and a wind tab for complete arming.

It is still a further object of this invention to provide a two stage omni-directional impact fuze which provides a visual indication of first stage arming.

It is still another object of this invention to provide a two stage omni-directional impact fuze which is economical to produce and which utilizes conventional currently available components that lend themselves to standard mass producing manufacturing techniques.

For a better understanding of the present invention together with other and further objects thereof reference is made to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

DESCRIPTION OF THE DRAWING FIG. 1 is a top elevational view of the fuze of this invention shown partly in cross-section with its wind tab and fuze case top removed and in its unarmed position;

FIG. 2 is a side elevational view of the fuze of this invention taken along lines 2-2 of FIG. 1;

FIG. 3 is a top elevational view of the fuze of this invention shown partly in cross-section with its wind tab and fuze case top removed and in its first stage of operation;

FIG. 4 is a side elevational view of the fuze of this invention taken along lines 4-4 ofFIG. 3;

FIG. 5 is a top elevational view of the fuze of this invention shown partly in cross-section with its wind tab and fuze case top removed and in its fully armed stage of operation; and

FIG. 6 is a side elevational view of the fuze of this invention taken along lines 6-6 of FIG. 5 and showing its wind tab in the removed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to FIGS. 1 and 2 of the drawing which shows the fuze 10 of this invention in its unarmed posi tion. The fuze 10 is made up ofa fuze case body 12 which is mounted within any suitable type of munition or submissile case 14. A fuze case guide 16 is located between the munition l4 and the fuze case body 12. This guide 16 is fixedly mounted to case 14 by any suitable securing means such as index tab 22. The guide 16 further has a plurality of grooves 18 therein which admit suitable securing means such as index tabs 20 mounted on the fuze case body 12 to prevent the rotation thereof within munition case 14.

The fuze case body 12 as seen in FIG. 2 has a top portion 24 which is fixedly secured to the body 12. This top portion 24 is of a conical configuration and has its uppermost portion at the midpoint thereof. The fuze case body 12 is located within the guide 16 and is held in its lowermost position (shown in FIGS. 1 and 2) against any conventional seal 25 by a cover or wind tab 26. This wind tab 26 has a plurality of rotor stops 28 fixedly secured thereto. The stops 28 each have a notch 29 therein for engaging the outside edge of a rotor 30 in order to maintain the fuze case 12 in this lowermost position.

The rotor 30 is rotatably mounted within the fuze body 12 on a rotor pin 32 fixedly secured to the bottom of guide 16. The rotor pin 32 has thereon a plurality of bearings 34 made of any suitable material, such as Teflon, which engage opposite sides of an extended element 36 formed on the bottom 38 of rotor 30.

The rotor 30 also has mounted therein a stab detonator 68 which is initially located 180 away from the firing pin 35. Still referring to FIG. 1, any suitable biasing means such as spring 40 is fixedly secured at one end to a rotor spring pin 42 mounted on fuze case body 12 and at the other end presses against the end 33 of cutout 72. This spring 40 causes the rotation of the rotor 30 from its position shown in FIGS. 1 and 2 to its final position 180 away, shown in FIGS. & 6.

Preventing the rotation of rotor 30 is a pair of pressure actuated locking arm assemblies 46. Each of the locking arm assemblies 46 is made up of locking arm 47 fixedly secured at one end thereof to case 12 and engaging at the other end a locking tab 48 located on the top portion 50 of rotor 30. A diaphragm 52 made of any suitable material, such as rubber, is fixedly secured to case 12 and adjacent the center of locking arm 47. In order to move the locking arm 47 out of engagement with the rotor locking tab 48 a plurality of pressure windows 54 are located within fuze case body 12 and guide 16. The windows 54 are utilized in conjunction with a plurality of slits 56 within the munition case 14 allowing for the pressurization and movement of the locking arm assembly 46 in a manner to be explained in detail hereinbelow.

Forming another essential part of the fuze of this invention is any suitable weight, such as actuator ball 58. This actuator ball 58 is located within the fuze case body 12 adjacent the underside of the uppermost portion of the conical fuze case top 24, resting upon a firing pin lever assembly 60. The firing pin lever assembly 60 is made up of a circular central portion 61 and a pair of elongated end portions 63 and 65. A firing pin 35 is mounted in one elongated portion 63 (see FIG. 6), while the other elongated end portion 65 is pivotally mounted by any suitable mounting means 64 to the fuze. As seen in FIG. 6, this mounting means 64 has a slotted member 67 fixedly secured to case 12 with elongated portion 65 freely extending therebetween. The circular central portion 61 of firing pin lever assembly 60 is also ofa conical configuration and has its conical portion in a lowermost position directly opposed to the conical portion of fuze case top 24.

Another conventional biasing means such as leaf spring 62 is located between the rotor 30 and the firing pin lever assembly 60. The action of spring 62 raises fuze case body 12 from its lowermost position shown in FIG. 2 (wherein the case 12 rests against the seal to its uppermost or first stage arming position shown in FIG. 4. The above operation takes place when the locking arm assemblies 46 disengage from locking tabs 48. The movement of the locking arm assemblies 46 allows for the substantially simultaneous rotation of rotor under the influence of spring to its position in FIGS. 3 and 4 and for the disengagement of notches 29 from the outside edge of top portion of rotor 30. During this procedure a cavity 27 is formed between the wind tab 26 and the munition case 14 (as shown in FIG. 4) for visual observation of the first stage arming.

Subsequent removal of the wind tab 26 (as shown in FIGS. 5 and 6) also removes the rotor stops 28. This action allows for the further rotation of rotor 30 under the influence of spring 40 until the end 70 of a cutout 72 located within rotor 30 abuts rotor spring pin 42 (FIG. 5). As shown in FIGS. 5 and 6, the firing pin 35 is now directly above the stab detonator 68 and the booster 74. In this position the firing pin 35 is capable of detonating the explosive 76 located within the munition case 14 in the manner set forth hereinbelow.

MODE OF OPERATION After separation of the munition, such as a missile from the delivery aircraft or the like, a central safing and arming mechanism activates a conventional warhead pressurization system (not shown) which subjects each submissile or mu nition case 14 to elevated pressures.

Referring to FIGS. 1 and 2, the arming pressure enters the fuze IQ of this invention through pressure windows or slits 56 in the munition case 14 and causes two diametrically opposed pressure actuated locking arm assemblies 46 to be deflected inward by rubber diaphragms 52. This motion unlocks the locking tabs 48 on rotor 30, thus permitting the rotor 30 to advance under the action of spring 40 until rotor locking tabs 48 contact the wind tab rotor stops 28 on wind tab 26. With the rotor 30 in this position, the wind tab rotor stops 28 are located within rotor cutouts 31 and the wind tab 26 is unlocked from the fuze 10.

Furthermore, after deployment of the fuze 10 from the missile (as best shown in FIGS. 3 and 4), a cavity 27 formed by the wind tab 26 and the munition case 14 is opened by movement of the fuze case body 12 relative to the fuze case guide 16 under the influence of leaf springs 62 and 72. The first stage arming of fuze 10 of this invention is now complete. During submissile handling and warhead loading, this same cavity 27 provides a visual indication of first stage arming or unsafe condition.

The tapered end 66 of munition case 14 permits the air stream to act upon the bottom surface of wind tab 26, thus forcing the wind tab 26 from the fuze case 12. The rotor 30 is now free to advance under the influence of spring 40, past wind tab rotor stop 28 and against rotor spring pin 42 (as shown in FIGS. 5 and 6), thus completing the arming sequence.

With the fuze 10 of this invention in the position shown in FIGS. 5 and 6 and prior to impact, the firing pin 35 is restrained from contact with the stab detonator 68 on rotor 30 by spring 62 positioned between the rotor 30 and firing pin lever assembly 60. Upon impact, if the forward end of the submissile contacts the target, the spherical weight 58 and firing pin lever 60 depress the spring 62 and force the firing pin 35 into the stab detonator 68, thus initiating the explosive train. If the submissile impacts parallel to its longitudinal axis, the spherical weight 58 moves radially in the direction of impact. This motion of the weight 58 forces the firing pin lever 60 to move toward the rotor 30 and causes the firing pin 35 to stab the detonator 68. If the aft end of the submissile contacts the target, top portion 24 of the fuze case (which extends beyond the submissile aft end and is in contact with the spherical weight) forces the spherical weight 58 and firing pin lever 60 to move toward the rotor 30 thus causing the firing pin 35 to stab the detonator 68. If the submissile impacts in any attitude other than those previously discussed, a combination of the above reactions will cause the fuze to initiate the explosive train.

Although the invention has been described with reference to a particular embodiment, it will be understood to those skilled in the art that the invention is capable of a variety of alternate embodiments within the spirit and scope of the appended claims.

We claim:

I. A two stage omni-directional impact fuze comprising a fuze guide, a fuze body mounted within said guide, a rotor rotatably mounted within said body, means operably connected to said rotor for causing rotation thereof, a wind tab, said wind tab having locking means thereon for engaging said rotor to prevent removal of said wind tab, at least one locking arm assembly, said locking arm assembly being movably mounted on said body and capable of preventing the rotation of said rotor in the unarmed position, and a firing pin lever assembly pivotally mounted at one end thereof to said body whereby upon movement of said locking arm assembly said rotor rotates to the first stage arming position thereby disengaging said wind tab locking means from said rotor and upon complete removal of said wind tab from said fuze body said rotor rotates to the fully armed position.

2. A two stage omni-directional impact fuze as defined in claim 1 wherein said fuze body has a top portion and a spherical weight is located between said firing pin lever assembly and said top portion of said body whereby movement of said spherical weight in any direction while said fuze is in said fully armed position causes movement of said firing pin lever assembly.

3. A two-stage omni-directional impact fuze as defined in claim 2 further comprising a biasing means, said biasing means being mounted between said rotor and said firing pin assembly for moving said body and said wind tab relative to said guide during the first stage arming of said fuze.

4. A two-stage omni-directional impact fuze as defined in claim 3 wherein said tiring pin lever assembly has a firing pin mounted at the other end thereof and said rotor has a detonator thereon, whereby in the unarmed position of said fuze said firing pin and said detonator are 180 apart and in said fully armed position said firing pin and said detonator are in alignment with each other.

5. A two-stage omni-directional impact fuze as defined in claim 4 wherein said rotor has at least one rotor locking tab thereon and said wind tab has a stop means thereon, whereby in said unarmed position said rotor locking tab engages said locking arm assembly and in said first stage arming position said rotor locking tab engages said stop means on said wind tab.

6. A two-stage omni-directional impact fuze as defined in claim 5 wherein said rotor has a cutout portion therein and a rotor stop is fixedly secured to said body whereby in said fully armed position said rotor stop abuts the end of said cutout portion.

7. A two-stage omni-directional impact fuze as defined in claim 6 wherein said fuze guide and said fuze body have a pressure window therein adjacent said locking arm assembly.

8. A two stage omni-directional impact fuze as defined in claim 7 wherein said top portion of said body and said firing pin lever assembly are of a converging conical configuration.

9. A two stage omni-directional impact fuze as defined in claim 8 further comprising a rotor pin fixedly secured to said guide and protruding into said body, said rotor being rotatably mounted thereon.

10. A two stage omni-directional impact fuze as defined in claim 9 wherein said biasing means is a leaf spring. 

1. A two stage omni-directional impact fuze comprising a fuze guide, a fuze body mounted within said guide, a rotor rotatably mounted within said body, means operably connected to said rotor for causing rotation thereof, a wind tab, said wind tab having locking means thereon for engaging said rotor to prevent removal of said wind tab, at least one locking arm assembly, said locking arm assembly being movably mounted on said body and capable of preventing the rotation of said rotor in the unarmed position, and a firing pin lever assembly pivotally mounted at one end thereof to said body whereby upon movement of said locking arm assembly said rotor rotates to the first stage arming position thereby disengaging said wind tab locking means from said rotor and upon complete removal of said wind tab from said fuze body said rotor rotates to the fully armed position.
 2. A two stage omni-directional impact fuze as defined in claim 1 wherein said fuze body has a top portion and a spherical weight is located between said firing pin lever assembly and said top portion of said body whereby movement of said spherical weight in any direction while said fuze is in said fully armed position causes movement of said firing pin lever assembly.
 3. A two-stage omni-directional impact fuze as defined in claim 2 further comprising a biasing means, said biasing means being mounted between said rotor and said firing pin assembly for moving said body and said wind tab relative to said guide during the first stage arming of said fuze.
 4. A two-stage omni-directional impact fuze as defined in claim 3 wherein said firing pin lever assembly has a firing pin mounted at the other end thereof and said rotor has a detonator thereon, whereby in the unarmed position of said fuze said firing pin and said detonator are 180* apart and in said fully armed position said firing pin and said detonator are in alignment with each other.
 5. A two-stage omni-directional impact fuze as defined in claim 4 wherein said rotor has at least one rotor locking tab thereon and said wind tab has a stop means thereon, whereby in said unarmed position said rotor locking tab engages said locking arm assembly and in said first stage arming position said rotor locking tab engages said stop means on said wind tab.
 6. A two-stage omni-directional impact fuze as defined in claim 5 wherein said rotor has a cutout portion therein and a rotor stop is fixedly secured to said body whereby in said fully armed position said rotor stop abuts the end of said cutout portion.
 7. A two-stage omni-directional impact fuze as defined in claim 6 wherein said fuze guide and said fuze body have a pressure window therein adjacent said locking arm assembly.
 8. A two stage omni-directional impact fuze as defined in claim 7 wherein said top portion of said body and said firing pin lever assembly are of a converging conical configuration.
 9. A two stage omni-directional impact fuze as defined in claim 8 further comprising a rotor pin fixedly secured to said guide and protruding into said body, said rotor being rotatably mounted thereon.
 10. A two stage omni-directional impact fuze as defined in claim 9 wherein said biasing means is a leaf spring. 